Liquid crystal composition and liquid crystal display device

ABSTRACT

A liquid crystal composition having a nematic phase comprising two components, wherein the first component is at least one compound selected from the group of compounds represented by formula (1), and the second component is at least one compound selected from the group of compounds represented by formula (2), and the third component is at least one compound selected from the group of compounds represented by formula (3): 
                         
wherein R 1  and R 2  are each independently alkyl having 1 to 12 carbons, alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons or alkenyl having 2 to 12 carbons in which arbitrary hydrogen is replaced by fluorine; ring A and ring B are each independently 1,4-cyclohexylene, 1,4-phenylene; 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene; and X 1 , X 2 , X 3  and X 4  are each independently hydrogen or fluorine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to Japanese PatentApplication No. JP 2008-103726, filed Apr. 11, 2008, which applicationis expressly incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a liquid crystal composition suitable for usein an active matrix (AM) device, and an AM device containing thecomposition. More specifically, the invention relates to a liquidcrystal composition having a positive dielectric anisotropy, and alsorelates to a device of a twisted nematic (TN) mode, an opticallycompensated bend (OCB) mode, an in-plane switching (IPS) mode or apolymer sustained alignment (PSA) mode containing the composition.

2. Related Art

In a liquid crystal display device, classification based on an operatingmode of liquid crystals includes phase change (PC), twisted nematic(TN), super twisted nematic (STN), electrically controlled birefringence(ECB), optically compensated bend (OCB), in-plane switching (IPS),vertical alignment (VA), polymer sustained alignment (PSA) and so forth.Classification based on a driving mode of the device includes a passivematrix (PM) and an active matrix (AM). PM is further classified intostatic, multiplex and so forth, and AM is classified into a thin filmtransistor (TFT), a metal insulator metal (MIM) and so forth. TFT isfurther classified into amorphous silicon and polycrystal silicon. Thelatter is classified into a high temperature type and a low temperaturetype according to a production process. Classification based on a lightsource includes a reflection type utilizing a natural light, atransmission type utilizing a backlight and a semi-transmission typeutilizing both the natural light and the backlight.

These devices contain a liquid crystal composition having suitablecharacteristics. The liquid crystal composition has a nematic phase.General characteristics of the composition should be improved to obtainan AM device having good general characteristics. Table 1 belowsummarizes a relationship between the general characteristics of thetwo. The general characteristics of the composition will be explainedfurther based on a commercially available AM device. A temperature rangeof a nematic phase relates to the temperature range in which the devicecan be used. A desirable maximum temperature of the nematic phase isapproximately 70° C. or more and a desirable minimum temperature isapproximately −10° C. or less. The viscosity of the composition relatesto the response time of the device. A short response time is desirablefor displaying a moving image. Accordingly, a small viscosity of thecomposition is desirable. A small viscosity at a low temperature is moredesirable.

TABLE 1 General Characteristics of Liquid Crystal Composition and AMDevice General Characteristics of a General Characteristics NoComposition of an AM Device 1 Temperature range of a Usable temperaturerange is wide nematic phase is wide 2 Viscosity is small¹⁾ Response timeis short 3 Optical anisotropy is suitable Contrast ratio is large 4Dielectric anisotropy is Threshold voltage is low, electric positivelyor negatively large power consumption is small, and contrast ratio islarge 5 Specific resistance is large Voltage holding ratio is large, anda contrast ratio is large 6 It is stable to ultraviolet light Servicelife is long and heat ¹⁾A liquid crystal composition can be injectedinto a cell in a short time.

The optical anisotropy of the composition relates to the contrast ratioof the device. A product (Δn) of the optical anisotropy (Δn) of thecomposition and the cell gap (d) of the device is designed to maximizethe contrast ratio. A suitable value of the product depends on the kindof operation mode. In a device having a TN mode, a suitable value isapproximately 0.45 μm. In this case, a composition having a largeoptical anisotropy is desirable for a device having a small cell gap. Alarge dielectric anisotropy of the composition contributes to a lowthreshold voltage, a small electric power consumption and a largecontrast ratio of the device. Accordingly, a large dielectric anisotropyis desirable. A large specific resistance of the composition contributesto a large voltage holding ratio and a large contrast ratio of thedevice. Accordingly, a composition having a large specific resistance isdesirable at room temperature and also at a high temperature in theinitial stage. A composition having a large specific resistance isdesirable at room temperature and also at a high temperature after ithas been used for a long time. A stability of the composition to anultraviolet light and heat relates to a service life of the liquidcrystal display device. In the case where the stability is high, thedevice has a long service life. These characteristics are desirable foran AM device used in a liquid crystal projector, a liquid crystaltelevision and so forth.

In an AM device having a TN mode, a composition having a positivedielectric anisotropy is used. In an AM device having a VA mode, acomposition having a negative dielectric anisotropy is used. In an AMdevice having an IPS mode, a composition having a positive or negativedielectric anisotropy is used. In an AM device having a PSA mode, acomposition having a positive or negative dielectric anisotropy is used.Examples of the liquid crystal composition having a positive anisotropyare disclosed in JP H3-504018A/1991, JP H10-95978A/1998, JPH10-101598A/1998, JP H10-101600A/1998.

In an AM device having a TN mode, a composition having a positivedielectric anisotropy is used. In an AM device having a VA mode, acomposition having a negative dielectric anisotropy is used. In an AMdevice having an IPS mode, a composition having a positive or negativedielectric anisotropy is used. In an AM device having a PSA mode, acomposition having a positive or negative dielectric anisotropy is used.Examples of the liquid crystal composition having a positive anisotropyare disclosed in JP H3-504018A/1991, JP H10-95978A/1998, JPH10-101598A/1998, JP H10-101600A/1998.

A desirable AM device is characterized as having a usable temperaturerange that is wide, a response time that is short, a contrast ratio thatis large, a threshold voltage that is low, a voltage holding ratio thatis large, a service life that is long, and so forth. Even onemillisecond shorter response time is desirable. Thus, the compositionhaving characteristics such as a high maximum temperature of a nematicphase, a low minimum temperature of a nematic phase, a small viscosity,a large optical anisotropy, a large dielectric anisotropy, a largespecific resistance, a high stability to an ultraviolet light, a highstability to heat, and so forth is especially desirable.

SUMMARY OF THE INVENTION

The invention concerns a liquid crystal composition having a nematicphase that includes two components, wherein the first component is atleast one compound selected from the group of compounds represented byformula (1), the second component is at least one compound selected fromthe group of compounds represented by formula (2), and the thirdcomponent is at least one compound selected from the group of compoundsrepresented by formula (3).

wherein R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring A and ring B are each independently 1,4-cyclohexylene,1,4-phenylene, 2-fluoro-1,4-phenylene, or 2,6-difluoro-1,4-phenylene;and X¹, X², X³ and X⁴ are each independently hydrogen or fluorine.

The invention also concerns a liquid crystal display device thatincludes the liquid crystal composition, and so forth.

DETAILED DESCRIPTION OF THE INVENTION

The terms used in the specification and claims are defined as follows.The liquid crystal composition and/or the liquid crystal display deviceof the invention may occasionally be expressed simply as “thecomposition” or “the device,” respectively. A liquid crystal displaydevice is a generic term for a liquid crystal display panel and a liquidcrystal display module. The “liquid crystal compound” is a generic termfor a compound having a liquid crystal phase such as a nematic phase, asmectic phase and so forth, and also for a compound having no liquidcrystal phase but being useful as a component of a composition. Theuseful compound contains, for example, a 6-membered ring such as1,4-cyclohexylene and 1,4-phenylene, and a rod like molecular structure.An optically active compound or a polymerizable compound mayoccasionally be added to the composition. Even in the case where thecompound is a liquid crystal compound, the compound is classified intoan additive. At least one compound selected from a group of compoundsrepresented by formula (1) may be abbreviated to “the compound (1).” The“compound (1)” means one compound or two or more compounds representedby formula (1). The other formulas are applied with the same rules. Theterm “arbitrary” means that not only the position but also the numberare arbitrary, but the case where the number is zero is not included.

A higher limit of a temperature range of a nematic phase may beabbreviated to “a maximum temperature.” A lower limit of a temperaturerange of a nematic phase may be abbreviated to “a minimum temperature.”“A specific resistance is large” means that the composition has a largespecific resistance at room temperature and also nearly at the maximumtemperature of a nematic phase in the initial stage, the composition hasa large specific resistance at room temperature and also nearly at themaximum temperature of a nematic phase even after it has been used for along time. “A voltage holding ratio is large” means that a device has alarge voltage holding ratio at room temperature and also nearly at themaximum temperature of a nematic phase in the initial stage, the devicehas a large voltage holding ratio at room temperature and also nearly atthe maximum temperature of a nematic phase even after it has been usedfor a long time. In the description of the characteristics such asoptical anisotropy, the characteristics of the composition such as theoptical anisotropy and so forth are values measured in the methodsdisclosed in Examples. The first component includes one compound or twoor more compounds. “A ratio of the first component” means the percentageby weight (% by weight) of the first component based on the total weightof liquid crystal composition. A ratio of the second component and soforth are applied with the same rule. A ratio of an additive mixed withthe composition means the percentage by weight (% by weight) based onthe total weight of liquid crystal composition.

In the chemical formulas of the component compounds, symbol R¹ is usedin plural compounds. In these compounds, any two R¹ may be the same asor different from each other. In one case, for example, R¹ of thecompound (1) is ethyl and R¹ of the compound (2) is ethyl. In anothercase, R¹ of the compound (1) is ethyl and R¹ of the compound (2) ispropyl. This rule is also applicable to the symbols R², R³ and so forth.CL in the chemical formulas is chlorine.

One of the advantages of the invention is to provide a liquid crystalcomposition that satisfies at least one characteristic among thecharacteristics such as a high maximum temperature of a nematic phase, alow minimum temperature of a nematic phase, a small viscosity, a largeoptical anisotropy, a large dielectric anisotropy, a large specificresistance, a high stability to ultraviolet light and a high stabilityto heat and so forth. Another advantage of the invention is to provide aliquid crystal composition that is properly balanced regarding at leasttwo characteristics among many characteristics. Another advantage of theinvention is to provide a liquid crystal display device that containsthe liquid crystal composition. Another of the advantage of theinvention is to provide a liquid crystal composition that has a largeoptical anisotropy, a large dielectric anisotropy, a high stability toultraviolet light and so forth, and is to provide an AM device that hasa short response time, a large voltage holding ratio, a large contrastratio, a long service life and so forth.

The invention has the following features.

1. A liquid crystal composition having a nematic phase comprising twocomponents, wherein the first component is at least one compoundselected from the group of compounds represented by formula (1), and thesecond component is at least one compound selected from the group ofcompounds represented by formula (2), and the third component is atleast one compound selected from the group of compounds represented byformula (3):

wherein R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring A and ring B are each independently 1,4-cyclohexylene,1,4-phenylene, 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene; X¹,X², X³ and X⁴ are each independently hydrogen or fluorine.

2. The liquid crystal composition according to item 1, wherein the firstcomponent is at least one compound selected from the group of compoundsrepresented by formulas (I-1) to (1-3):

wherein R³ is alkenyl having 1 to 12 carbons, or alkenyl having 2 to 12carbons; and X¹, X², X⁴, X⁵ and X⁶ are each independently hydrogen orfluorine.

3. The liquid crystal composition according to item 2, wherein the firstcomponent is at least one compound selected from the group of compoundsrepresented by formula (1-1).

4. The liquid crystal composition according to any one of items 1 to 3,wherein a ratio of the first component is from approximately 5% byweight to approximately 40% by weight, a ratio of the second componentis from approximately 15% by weight to approximately 65% by weight, anda ratio of the third component is from approximately 5% by weight toapproximately 40% by weight, based on the total weight of the liquidcrystal composition.

5. The liquid crystal composition according to any one of items 1 to 4,wherein the composition further comprises at least one compound selectedfrom the group of compounds represented by formula (4) as a fourthcomponent:

wherein R¹ is alkyl having 1 to 12 carbons, alkoxy having 1 to 12carbons, alkenyl having 2 to 12 carbons or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine; X¹, X² areeach independently hydrogen or fluorine; ring C is independently1,4-cyclohexylene, 1,4-phenylene, 3-fluoro-1,4-phenylene,3,5-difluoro-1,4-phenylene 1,3-dioxane-2,5-diyl, or pyrimidine-2,5-diyl;Z¹ is independently a single bond, ethylene, carbonyloxy ordifluoromethyleneoxy; Y¹ is fluorine or chlorine; p is 1, 2 or 3.

6. The liquid crystal composition according to item 5, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formulas (4-1) to (4-17):

wherein R³ is alkyl having 1 to 12 carbons or alkenyl having 2 to 12carbons; Y¹ is fluorine or chlorine.

7. The liquid crystal composition according to item 6, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-10).

8. The liquid crystal composition according to item 6, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-12).

9. The liquid crystal composition according to item 6, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-13).

10. The liquid crystal composition according to item 6, wherein thefourth component is at least one compound selected from the group ofcompounds represented by formula (4-17).

11. The liquid crystal composition according to item 6, wherein thefourth component is a mixture of at least one compound selected from thegroup of compounds represented by formula (4-13) and at least onecompound selected from the group of compounds represented by formula(4-17).

12. The liquid crystal composition according to any one of items 5 to11, wherein a ratio of the fourth component is from approximately 5% byweight to approximately 65% by weight based on the total weight of theliquid crystal composition.

13. The liquid crystal composition according to any one of items 1 to12, wherein the composition further comprises at least one compoundselected from the group of compounds represented by formulas (5-1) and(5-2) as a fifth component:

wherein R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons, alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring D is 1,4-cyclohexylene or 1,4-phenylene; ring E and ringF are each independently 1,4-cyclohexylene, 1,4-phenylene, or2-fluoro-1,4-phenylene; Z² is independently a single bond, ethylene, orcarbonyloxy; and q is 1 or 2.

14. The liquid crystal composition according to item 13, wherein thefifth component is at least one compound selected from the group ofcompounds represented by formulas (5-1-1), (5-2-1) to (5-2-5):

wherein R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons, oralkenyl having 2 to 12 carbons in which arbitrary hydrogen is replacedby fluorine.

15. The liquid crystal composition according to item 14, wherein thewherein the fifth component is at least one compound selected from thegroup of compounds represented by formula (5-1-1).

16. The liquid crystal composition according to item 14, wherein thefifth component is at least one compound selected from the group ofcompounds represented by formula (5-2-1).

17. The liquid crystal composition according to item 14, wherein thefifth component is a mixture of at least one compound selected from thegroup of compounds represented by formula (5-1-1) and at least onecompound selected from the group of compounds represented by formula(5-2-1).

18. The liquid crystal composition according to any one of items 13 to17, wherein a ratio of the fifth component is from approximately 3% byweight to approximately to 40% by weight based on the total weight ofthe liquid crystal composition.

19. The liquid crystal composition according to any one of items 1 to18, wherein the composition has a maximum temperature of a nematic phaseof approximately 65° C. or more, an optical anisotropy (25° C.) at awavelength of 589 nm of approximately 0.08 or more, and a dielectricanisotropy (25° C.) at a frequency of 1 kHz of approximately 2 or more.

20. A liquid display device that includes the liquid crystal compositionaccording to any one of items 1 to 19.

21. The liquid crystal display device according to item 20, wherein theliquid crystal display device has an operation mode of a TN mode, an OCBmode, an IPS mode or a PSA mode, and has a driving mode of an activematrix mode.

The invention further includes: (1) the composition described above,wherein the composition further contains an optically active compound;(2) the composition described above, wherein the composition furthercontains an additive, such as an antioxidant, an ultraviolet lightabsorbent, an antifoaming agent, a polymerizable compound, apolymerization initiator and so forth; (3) an AM device containing thecomposition described above; (4) a device having a TN, ECB, OCB, IPS orPSA mode, containing the composition described above; (5) a device of atransmission type, containing the composition described above; (6) useof the composition described above as a composition having a nematicphase; and (7) use as an optically active composition by adding anoptically active compound to the composition described above.

The composition of the invention will be explained in the followingorder. First, the constitution of component compounds in the compositionwill be explained. Second, the main characteristics of the componentcompounds and the main effects of the compounds on the composition willbe explained. Third, combinations of components in the composition,desirable ratios of the component compounds and the basis thereof willbe explained. Fourth, a desirable embodiment of the component compoundswill be explained. Fifth, examples of the component compound will beshown. Sixth, additives that may be added to the composition will beexplained. Seventh, the preparation methods of the component compoundwill be explained. Lastly, use of the composition will be explained.

First, the constitution of component compounds in the composition willbe explained. The composition of the invention is classified into thecomposition A and the composition B. The composition A may furthercontain other compounds such as another liquid crystal compound, anadditive, an impurity, and so forth. “Another liquid crystal compound”is different from the compound (1), the compound (2), the compound (3),the compound (4), the compound (5-1) and the compound (5-2). Such aliquid crystal compound is mixed with the composition for the purpose ofadjusting the characteristics of the composition. Among the other liquidcrystal compounds, an amount of a cyano compound is desirably small fromthe viewpoint of stability to heat or ultraviolet light. The moredesirable amount of a cyano compound is 0% by weight. The additiveincludes an optically active compound, an antioxidant, an ultravioletlight absorbent, a coloring matter, an antifoaming agent, apolymerizable compound, a polymerization initiator and so forth. Theimpurity is a compound and so forth contaminated in the process such asthe synthesis of a component compound and so forth. Even when thecompound is a liquid crystal compound, it is classified into an impurityherein.

The composition B essentially consists of the compounds selected fromthe compound (1), the compound (2), the compound (3), the compound (4),the compound (5-1) and the compound (5-2). The term “essentially” meansthat the composition does not contain a liquid crystal compound that isdifferent from these compounds. The term “essentially” means that thecomposition may further contain the additive and the impurity and soforth. The components of the composition B are fewer than those of thecomposition A. The composition B is preferable to the composition A fromthe viewpoint of cost reduction. The composition A is preferable to thecomposition B, because characteristics of the composition A can befurther adjusted by mixing other liquid crystal compounds.

Second, the main characteristics of the component compounds and the maineffects of the compounds on the composition will be explained. The maincharacteristics of the component compounds are summarized in Table 2. InTable 2, the symbol L represents large or high, the symbol M representsa middle degree, and the symbol S represents small or low. The symbolsL, M and S are classification based on qualitative comparison among thecomponent compounds.

TABLE 2 Characteristics of Compounds Compound (1) (2) (3) (4) (5-1)(5-2) Maximum temperature M S M S-L S L Viscosity M-L S M S-L S M-LOptical anisotropy M-L S L S-L M M-L Dielectric anisotropy L 0 0 M-L 0 0Specific resistance L L L L L L

The main effects of the component compounds to the characteristics ofthe composition upon mixing the component compounds in the compositionare as follows. The compound (1) increases the dielectric anisotropy.The compound (2) decreases the viscosity. The compound (3) increases theoptical anisotropy. The compound (4) increases the dielectricanisotropy. The compound (5-1) decreases the viscosity. The compound(5-2) increases the maximum temperature.

Third, combinations of components in the composition, desirable ratiosof the component compounds and the basis thereof will be explained.Examples of the combinations of the components in the compositioninclude (first component+second component+third component), (firstcomponent+second component+third component+fourth component), (firstcomponent+second component+third component+fifth component) and (firstcomponent+second component+third component+fourth component+fifthcomponent).

A desirable ratio of the first component is approximately 5% by weightor more for increasing the dielectric anisotropy, and is approximately40% by weight or less for decreasing the minimum temperature. A moredesirable ratio is from approximately 5% by weight to approximately 35%by weight. A particularly desirable ratio is from approximately 5% byweight to approximately 30% by weight.

A desirable ratio of the second component is approximately 15% by weightor more for increasing the optical anisotropy, and is approximately 65%by weight or less for increasing the dielectric anisotropy. A moredesirable ratio is from approximately 15% by weight to approximately 60%by weight. A particularly desirable ratio is from approximately 20% byweight to approximately 55% by weight.

A desirable ratio of the third component is approximately 5% by weightor more for increasing the optical anisotropy, and is approximately 40%by weight or less for decreasing the minimum temperature. A moredesirable ratio is from approximately 5% by weight to approximately 35%by weight. A particularly desirable ratio is from approximately 5% byweight to approximately 30% by weight.

The fourth component is particularly suitable for preparing acomposition having a large dielectric anisotropy. A desirable ratio ofthe component is from approximately 5% by weight to approximately 65% byweight. A more desirable ratio is from approximately 5% by weight toapproximately 60% by weight. A particularly desirable ratio is fromapproximately 5% by weight to approximately 55% by weight. The fifthcomponent is particularly suitable for preparing a composition having alarge dielectric anisotropy. A desirable ratio of the component is fromapproximately 3% by weight to approximately 40% by weight. A moredesirable ratio is from approximately 3% by weight to approximately 35%by weight. A particularly desirable ratio is from approximately 3% byweight to approximately 30% by weight.

Fourth, a desirable embodiment of the component compound will beexplained. R¹ and R² are each independently alkyl having 1 to 12carbons, alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbonsor alkenyl having 2 to 12 carbons in which arbitrary hydrogen isreplaced by fluorine. Desirable R¹ is alkyl having 1 to 12 carbons forincreasing the stability to ultraviolet light or heat, or alkenyl having2 to 12 carbons for decreasing the minimum temperature. Desirable R² isalkenyl having 2 to 12 carbons for decreasing the minimum temperature ordecreasing the viscosity. R³ is alkyl having 1 to 12 carbons or alkenylhaving 2 to 12 carbons. Desirable R³ is alkyl having 1 to 12 carbons forincreasing the stability to ultraviolet light or heat, and so forth.Desirable alkyl is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl,or octyl. More desirable alkyl is ethyl, propyl, butyl, pentyl, orheptyl for decreasing a viscosity.

Desirable alkoxy is methoxy, ethoxy, propoxy, butoxy, pentyloxy,hexyloxy, or heptyloxy. More desirable alkoxy is methoxy or ethoxy fordecreasing a viscosity.

Desirable alkenyl is vinyl, 1-propenyl, 2-propenyl, 1-butenyl,2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl,1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl. More desirablealkenyl is vinyl, 1-propenyl, 3-butenyl, or 3-pentenyl for decreasing aviscosity. A desirable configuration of —CH═CH— in these alkenylsdepends on the position of a double bond. Trans is desirable in thealkenyl such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl,3-pentenyl, and 3-hexenyl for decreasing the viscosity. Cis is desirablein the alkenyl such as 2-butenyl, 2-pentenyl and 2-hexenyl. In thesealkenyls, linear alkenyl is preferable to branched alkenyl.

Preferred examples of alkenyl in which arbitrary hydrogen is replaced byfluorine include 2,2-difluorovinyl, 3,3-difluoro-2-propenyl,4,4-difluoro-3-butenyl, 5,5-difluoro-4-pentenyl and6,6-difluoro-5-hexenyl. More preferred examples thereof include2,2-difluorovinyl and 4,4-difluoro-3-butenyl for decreasing theviscosity.

Ring A and ring B are each independently 1,4-cyclohexylene,1,4-phenylene, 2-fluoro-1,4-phenylene, or 2-6-difluoro-1,4-phenylene.Desirable ring A is 1,4-phenylene for increasing the optical anisotropy.Desirable ring B is 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylenefor decreasing the minimum temperature. Ring C is 1,4-cyclohexylene,1,4-phenylene, 2-fluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene,1,3-dioxan-2,5-diyl, or pyrimidine-2,5-diyl, and when p is more than 2,two or three rings C may be the same as or different from each other.Desirable ring C is 1,4-phenylene for increasing the optical anisotropy,or 2,6-difluoro-1,4-phenylene for decreasing the minimum temperature.Ring D is 1,4-cyclohexylene or 1,4-phenylene. Ring E and ring F are eachindependently 1,4-cyclohexylene, 1,4-phenylene, or2-fluoro-1,4-phenylene and when q is 2, two rings E may be may be thesame as or different from each other. When the rings are2-fluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 1,3-dioxan-2,5-diylor pyrimidine-2,5-diyl, the directions of the rings are not limited.

Z¹ is a single bond, ethylene, carbonyloxy or difluoromethyleneoxy, andwhen p is 2 or 3, any two Z¹ may be the same as or different from eachother. Desirable Z¹ is difluoromethyleneoxy for increasing thedielectric anisotropy. Z² is a single bond, ethylene or carbonyloxy,when q is 2 two Z² may be the same as or different from each other.Desirable Z² is a single bond for decreasing the viscosity.

X¹, X², X³, X⁴, X⁵ and X⁶ are each independently hydrogen or fluorine.At least one of X¹, X², X³, X⁴, X⁵ and X⁶ is preferably fluorine forincreasing the dielectric anisotropy or decreasing the minimumtemperature.

Y¹ is fluorine or chlorine. Desirable Y¹ is fluorine for decreasing theminimum temperature.

Fifth, examples of the component compounds will be shown. In thedesirable compounds described below, R⁵ is linear alkyl having 1 to 12carbons. R⁶ and R⁷ are each independently linear alkyl having 1 to 12carbons or linear alkenyl having 2 to 12 carbons. In these desirablecompounds, trans is preferable to cis for the configuration of1,4-cyclohexylene for increasing the maximum temperature.

Desirable compounds (1) are the compounds (1-1-1) to (1-1-4), (1-2-1) to(1-2-3), (1-3-1) to (1-3-2). More desirable compounds (1) are thecompounds (1-1-1) and (1-2-1). Particularly desirable compounds (1) and(1-1-1). Desirable compounds (2) are the compounds (2-1). Desirablecompounds (3) are the compounds (3-1) and (3-2). More desirablecompounds (3) are the compounds (3-1). Desirable compounds (4) are thecompounds (4-1-1) to (4-17-1). More desirable compounds (4) are thecompounds (4-1-1), (4-2-1), (4-4-1) to (4-7-1), (4-10-1) to (4-17-1).Particularly desirable compounds (4) are the compounds (4-10-1) to(4-14-1), and (4-17-1). Desirable compounds (5-1) are the compounds(5-1-1-1). Desirable compounds (5-2) are the compounds (5-2-1-1) to(5-2-5-1). More desirable compounds (5-2) are the compounds (5-2-1-1)and (5-2-4-1). Particularly desirable compounds (5-2) are compounds(5-2-1-1).

Sixth, additives capable of being mixed with the composition will beexplained. The additives include an optically active compound, anantioxidant, an ultraviolet light absorbent, a coloring matter, anantifoaming agent, a polymerizable compound, a polymerization initiatorand so forth. An optically active compound is mixed in the compositionfor inducing a helical structure of liquid crystal to provide a twistangle. Examples of the optically active compound include the compounds(6-1) to (6-4) below. A desirable ratio of the optically active compoundis approximately 5% by weight or less, and a more desirable ratiothereof ranges from approximately 0.01% by weight to approximately 2%.

An antioxidant is mixed with the composition in order to avoid adecrease in specific resistance caused by heating in the air, or tomaintain a large voltage holding ratio at room temperature and alsonearly at the maximum temperature even after the device has been usedfor a long time.

Preferred examples of the antioxidant include the compound (7):

wherein n is an integer from 1 to 9. In the compound (7), desirable nare 1, 3, 5, 7, or 9. More desirable n are 1 or 7. When n is 1, thecompound (7) has a large volatility, and is effective in preventing thedecrease of specific resistance caused by heating in the air. When n is7, the compound (7) has a small volatility, and is effective inmaintaining a large voltage holding ratio at room temperature and alsonearly at the maximum temperature even after the device has been usedfor a long time. A desirable ratio of the antioxidant is approximately50 ppm or more in order to obtain the advantages thereof and isapproximately 600 ppm or less in order to prevent the maximumtemperature from being decreased and to prevent the minimum temperaturefrom being increased. A more desirable ratio is from approximately 100ppm to approximately 300 ppm.

Preferred examples of the ultraviolet light absorbent include abenzophenone derivative, a benzoate derivative and a triazolederivative. A light stabilizer having steric hindrance such as an amineis also desirable. A desirable ratio of the absorbent and the stabilizeris approximately 50 ppm or more for obtaining the advantages thereof andis approximately 10,000 ppm or less for preventing the maximumtemperature from being decreased and preventing the minimum temperaturefrom being increased. A more desirable ratio thereof ranges fromapproximately 100 ppm to approximately 10,000 ppm.

A dichroic dye such as an azo dye or an anthraquinone dye is mixed withthe composition to suit for a device of a guest host (GH) mode. Adesirable ratio of the dye ranges from approximately 0.01% by weight toapproximately 10% by weight. An antifoaming agent such as dimethylsilicone oil or methylphenyl silicone oil is mixed with the compositionfor preventing foaming from occurring. A desirable ratio of theantifoaming agent is approximately 1 ppm or more for obtaining theadvantages thereof and is approximately 1,000 ppm or less for preventingdisplay failure from occurring. A more desirable ratio thereof rangesfrom approximately 1 ppm to approximately 500 ppm.

A polymerizable compound is mixed with the composition for applying thecomposition to a device having a PSA (polymer sustained alignment) mode.Preferred examples of the polymerizable compound include compoundshaving a polymerizable group, such as acrylate, methacrylate, vinyl,vinyloxy, propenyl ether, vinylketone, epoxy such as oxirane, oxetane,and so forth. Particularly preferred examples thereof includederivatives of acrylate or methacrylate. A desirable ratio of thepolymerizable group is from approximately 0.05% by weight or more forobtaining the advantages thereof, and is approximately 10% by weight orless for preventing display failure from occurring. A more desirableratio is from approximately 0.1% by weight to approximately 2% byweight. The polymerizable compound is polymerized preferably in thepresence of a suitable initiator, such as a photopolymerizationinitiator and so forth, under radiation of ultraviolet light. Suitableconditions for polymerization and a suitable type and a suitable amountof the initiator have been known by a skilled person in the art and aredisclosed in literatures. Examples of the photopolymerization initiatorsuitable for radical polymerization include Irgacure 651 (trade name),Irgacure 184 (trade name) and Darocure 1173 (trade name), all producedby Ciba Japan K.K. The polymerizable compound preferably contains aphotopolymerization initiator in an amount of from approximately 0.1% byweight to approximately 5% by weight, and particularly preferablycontains a photopolymerization initiator in an amount of fromapproximately 1% by weight to approximately 3% by weight.

Seventh, the preparation methods of the component compounds will beexplained. These compounds can be prepared by known methods. Thepreparation method will be exemplified below. The compound (1-1-1) issynthesized by the method disclosed in JP H10-101598A/1998. The compound(2-1) is synthesized by the method disclosed in JP 144-30382 B/1992. Thecompound (3-1) is synthesized by the method disclosed in JP 2006-503130A. The compounds (4-5-1) and (4-7-1) are synthesized by the methoddisclosed in JP H2-233626 A/1990. The compounds ((5-2-4-1) aresynthesized by the method disclosed in JP H2-237949 A/1990. Theantioxidant is commercially available. The compound (7), wherein n is 1,is available, for example, from Sigma-Aldrich, Inc. The compound (7),wherein n is 7, and so forth are prepared by the method disclosed inU.S. Pat. No. 3,660,505.

The compounds for which preparation methods were not described above canbe prepared according to the methods described in Organic Syntheses(John Wiley & Sons, Inc.), Organic Reactions (John Wiley & Sons, Inc.),Comprehensive Organic Synthesis (Pergamon Press), New ExperimentalChemistry Course (Shin Jikken Kagaku Kouza) (Maruzen, Inc.), and soforth. The composition is prepared according to known methods using thecompounds thus obtained. For example, the component compounds are mixedand dissolved in each other by heating.

Last, use of the composition will be explained. The compositions of theinvention mainly have a minimum temperature of approximately −10° C. orless, a maximum temperature of approximately 70° C. or more, and anoptical anisotropy of approximately 0.07 to approximately 0.20. Thedevice containing the composition has a large voltage holding ratio. Thecomposition is suitable for an AM device. The composition is suitableespecially for an AM device of a transmission type. The compositionhaving an optical anisotropy of approximately 0.08 to approximately 0.25and further having an optical anisotropy of approximately 0.10 toapproximately 0.30 may be prepared by controlling ratios of thecomponent compounds or by mixing other liquid crystal compounds. Thecomposition can be used as a composition having a nematic phase and asan optically active composition by adding an optically active compound.

The composition can be used for an AM device. It can be also used for aPM device. The composition can be also used for an AM device and a PMdevice having a mode such as PC, TN, STN, ECB, OCB, IPS, VA, PSA and soforth. It is desirable to use the composition for an AM device having aTN, OCB or IPS mode. These devices may be of a reflection type, atransmission type or a semi-transmission type. It is desirable to usethe composition for a device of a transmission type. It can be used foran amorphous silicon-TFT device or a polycrystal silicon-TFT device. Thecomposition is also usable for a nematic curvilinear aligned phase(NCAP) device prepared by microcapsulating the composition, and for apolymer dispersed (PD) device in which a three dimensional net-workpolymer is formed in the composition, for example, a polymer network(PN) device.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the invention and specificexamples provided herein without departing from the spirit or scope ofthe invention. Thus, it is intended that the invention covers themodifications and variations of this invention that come within thescope of any claims and their equivalents.

The following examples are for illustrative purposes only and are notintended, nor should they be interpreted to, limit the scope of theinvention.

EXAMPLES

When a sample was a composition, it was measured as it was, and theobtained value is described here. When a sample was a compound, a samplefor measurement was prepared by mixing 15% by weight of the compound and85% by weight of mother liquid crystals. A value of characteristic ofthe compound was calculated by extrapolating from a value obtained bymeasurement. Namely: extrapolated value=(value measured forsample−0.85×value measured for mother liquid crystals)/0.15. When asmectic phase (or crystals) separated out at this ratio at 25° C., aratio of the compound and mother liquid crystals was changed step bystep in the order of (10% by weight/90% by weight), (5% by weight/95% byweight), (1% by weight/99% by weight), respectively. Values for amaximum temperature, optical anisotropy, viscosity, and dielectricanisotropy of the compound were obtained by the extrapolation.

The composition of the mother liquid crystals is as shown below. All thepercentages for the composition are percentage by weight.

Measurement of the characteristics was carried out according to thefollowing methods. Most methods are described in the Standard ofElectric Industries Association of Japan, EIAJ ED-2521 A or those withsome modifications.

Maximum Temperature of a Nematic Phase (NI; ° C.): A sample was placedon a hot plate in a melting point apparatus equipped with a polarizingmicroscope and was heated at the rate of 1° C. per minute. A temperaturewas measured when a part of the sample began to change from a nematicphase into an isotropic liquid. A higher limit of a temperature range ofa nematic phase may be abbreviated to “a maximum temperature.”

Minimum Temperature of a Nematic Phase (Tc; ° C.): A sample having anematic phase was put in a glass vial and then kept in a freezer attemperatures of 0° C., −10° C., −20° C., −30° C., and −40° C. for tendays, respectively, and a liquid crystal phase was observed. Forexample, when the sample remained in a nematic phase at −20° C. andchanged to crystals or a smectic phase at −30° C., Tc was expressed as≦−20° C. A lower limit of a temperature range of a nematic phase may beabbreviated to “a minimum temperature.”

Viscosity (η; measured at 20° C., mPa·s): A viscosity was measured bymeans of an E-type viscometer.

Rotation Viscosity (γ1; measured at 25° C.; mPa·s): Rotation viscositywas measured according to the method disclosed in M. Imai, et al.,Molecular Crystals and Liquid Crystals, vol. 259, p. 37 (1995). A samplewas placed in a device, in which a twist angle was 0°, and a distancebetween two glass substrates (cell gap) was 5 μm. The device was appliedwith a voltage in a range of from 16 V to 19.5 V stepwise by 0.5 V.After a period of 0.2 second with no application of voltage, voltageapplication was repeated with only one rectangular wave (rectangularpulse of 0.2 second) and application of no voltage (2 seconds). A peakcurrent and a peak time of a transient current generated by the voltageapplication were measured. Rotation viscosity was obtained from themeasured values and the calculating equation (8) in the literature by M.Imai, et al., p. 40. As the dielectric anisotropy necessary for thecalculation, the value was measured by the measuring method ofdielectric anisotropy described below with the device for measuring therotation viscosity.

Optical Anisotropy (refractive index anisotropy; Δn; measured at 25°C.): Measurement was carried out with an Abbe refractometer mounting apolarizing plate on an ocular using a light at a wavelength of 589 nm.The surface of a main prism was rubbed in one direction, and then asample was dropped on the main prism. Refractive index (n∥) was measuredwhen the direction of a polarized light was parallel to that of therubbing. Refractive index (n⊥) was measured when the direction of apolarized light was perpendicular to that of the rubbing. A value ofoptical anisotropy was calculated from the equation: Δn=n∥−n⊥.

Dielectric Anisotropy (Δ∈; measured at 25° C.): A sample was put in a TNdevice having a distance between two glass substrates (cell gap) of 9 μmand a twist angle of 80°. Sine waves (10 V, 1 kHz) were applied to thedevice, and a dielectric constant (∈∥) in a major axis direction of aliquid crystal molecule was measured after 2 seconds. Sine waves (0.5 V,1 kHz) were applied to the device, and a dielectric constant (∈⊥) in aminor axis direction of a liquid crystal molecule was measured after 2seconds. A value of a dielectric anisotropy was calculated from theequation: Δ∈=∈∥−∈⊥.

Threshold Voltage (Vth; measured at 25° C.; V): Measurement was carriedout with an LCD Evaluation System Model LCD-5100 made by OtsukaElectronics Co., Ltd. The light source was a halogen lamp. A sample waspoured into a TN device of a normally white mode, in which a cell gapbetween two glass plates was about 0.45/Δn (μm), and a twist angle was80°. Voltage to be applied to the device (32 Hz, rectangular waves) wasstepwise increased by 0.02 volt starting from 0 V up to 10 V. During thestepwise increasing, the device was irradiated with light in aperpendicular direction, and an amount of the light passing through thedevice was measured. Voltage-transmission curve was prepared, in which amaximum amount of a light corresponded to 100% transmittance, and aminimum amount of a light corresponded to 0% transmittance. Thresholdvoltage is a value at 90% transmittance.

Voltage Holding Ratio (VHR-1; measured at 25° C.; %): ATN device usedfor measurement has a polyimide-alignment film and the cell gap betweentwo glass plates is 5 μm. A sample was poured into the device, and thenthe device was sealed with an adhesive which is polymerized by theirradiation of an ultraviolet light. The TN device was applied andcharged with pulse voltage (60 microseconds at 5 V). Decreasing voltagewas measured for 16.7 milliseconds with High Speed Voltmeter and thearea A between a voltage curve and a horizontal axis in a unit cycle wasobtained. The area B was an area without decreasing. Voltage holdingratio is a percentage of the area A to the area B.

Voltage Holding Ratio (VHR-2; measured at 80° C.; %): ATN device usedfor measurement has a polyimide-alignment film and the cell gap betweentwo glass plates is 5 μm. A sample was poured into the device, and thenthe device was sealed with an adhesive which is polymerized by theirradiation of an ultraviolet light. The TN device was applied andcharged with pulse voltage (60 microseconds at 5 V). Decreasing voltagewas measured for 16.7 milliseconds with High Speed Voltmeter and thearea A between a voltage curve and a horizontal axis in a unit cycle wasobtained. The area B was an area without decreasing. Voltage holdingratio is a percentage of the area A to the area B.

Voltage Holding Ratio (VHR-3; measured at 25° C.; %): A voltage holdingratio was measured after irradiating with ultraviolet light to evaluatestability to ultraviolet light. A composition having large VHR-3 has alarge stability to ultraviolet light. A TN device used for measurementhas a polyimide-alignment film and the cell gap is 5 μm. A sample waspoured into the device, and then the device was irradiated with lightfor 20 minutes. The light source was a superhigh voltage mercury lampUSH-500D (produced by Ushio, Inc.), and the distance between the deviceand the light source is 20 cm. In measurement of VHR-3, a decreasingvoltage is measured for 16.7 milliseconds. VHR-3 is desirably 90% ormore, and more desirably 95% or more.

Voltage Holding Ratio (VHR-4; measured at 25° C.; %): A voltage holdingratio was measured after heating an TN device having a sample pouredtherein in a constant-temperature bath at 80° C. for 500 hours toevaluate stability to heat. A composition having large VHR-4 has a largestability to heat. In measurement of VHR-4, a decreasing voltage ismeasured for 16.7 milliseconds.

Response Time (r; measured at 25° C.; millisecond): Measurement wascarried out with an LCD Evaluation System Model LCD-5100 made by OtsukaElectronics Co., Ltd. Light source is a halogen lamp. Low-pass filterwas set at 5 kHz. A sample was poured into a TN device of a normallywhite mode, in which a cell gap between two glass plates was 5.0 μm, anda twist angle was 800. Rectangle waves (60 Hz, 5 V, 0.5 seconds) wereapplied to the device. During application, the device was irradiatedwith light in a perpendicular direction, and an amount of the lightpassing through the device was measured. A maximum amount of a lightcorresponds to 100% transmittance, and a minimum amount of a lightcorresponds to 0% transmission. Rise time (τr) is a period of timerequired for the change in transmittance from 90% to 10%. Fall time (τf)is a period of time required for the change in transmittance from 10% to90%. Response time is a sum of the rise time and the fall time thusobtained.

Specific Resistance (ρ; measured at 25° C.; Ωcm): 1.0 mL of a sample wascharged in a vessel equipped with electrodes. A direct current voltageof 10 V was applied to the vessel, and after lapsing 10 second from theapplication of voltage, the direct electric current was measured. Thespecific resistance was calculated by the equation: (specificresistance)={(voltage)×(electric capacity of vessel)}/{(directcurrent)×(dielectric constant of vacuum)}.

Gas Chromatographic Analysis: A Gas Chromatograph Model GC-14B made byShimadzu was used for measurement. The carrier gas was helium (2milliliters per minute). An evaporator and a detector (FID) were set upat 280° C. and 300° C., respectively. Capillary column DB-1 (length 30meters, bore 0.32 millimeters, film thickness 0.25 micrometers,dimethylpolysiloxane as stationary phase, no polarity) made by AgilentTechnologies, Inc. was used for the separation of the componentcompound. After the column had been kept at 200° C. for 2 minutes, itwas further heated to 280° C. at the rate of 5° C. per minute. A samplewas prepared in an acetone solution (0.1% by weight), and 1 microliterof the solution was injected into the evaporator. The recorder used wasa Chromatopac Model C-R5A made by Shimadzu or its equivalent. Thusobtained Gas chromatogram showed a retention time of a peak and a peakarea corresponding to the component compound.

Solvents for diluting the sample may also be chloroform, hexane, and soforth. The following capillary columns may also be used for separatingthe component compound: HP-1 made by Agilent Technologies Inc. (length30 meters, bore 0.32 millimeters, film thickness 0.25 micrometers),Rtx-1 made by Restek Corporation (length 30 meters, bore 0.32millimeters, film thickness 0.25 micrometers), and BP-1 made by SGEInternational Pty. Ltd. (length 30 meters, bore 0.32 millimeters, filmthickness 0.25 micrometers). In order to prevent compound peaks fromoverlapping, a capillary column CBP1-M50-025 (50 meters, bore 0.25millimeters, film thickness 0.25 micrometers) made by ShimadzuCorporation may be used.

The ratios of the liquid crystal compounds contained in the compositioncan also be calculated in the following manner. A liquid crystalcompound can be detected by gas chromatography. An area ratio of peakson a gas chromatogram corresponds to a ratio (molar number) of liquidcrystal compounds. In the case where the aforementioned capillarycolumns are used, correction coefficients of the liquid crystalcompounds can be regarded as 1. Accordingly, the ratio (% by weight) ofliquid crystal compounds is calculated from the area ratio of peaks.

The invention will be explained in detail by way of Examples. Theinvention is not limited by the Examples described below. The compoundsdescribed in the Comparative Examples and the Examples are expressed bythe symbols according to the definition in Table 3. In Table 3, theconfiguration of 1,4-cyclohexylene is trans. The parenthesized numbernext to the symbolized compounds in the Examples corresponds to thenumber of the desirable compound. The symbol (−) means other liquidcrystal compound. A ratio (percentage) of a liquid crystal compound ispercentage by weight (% by weight) based on the total weight of liquidcrystal compounds, and the liquid crystal compositions further containimpurities. Last, the characteristics of the composition are summarized.

TABLE 3 Method of Description of Compound using Symbols R-(A₁)-Z₁- . . .-Z_(n)-(A_(n))-R′ (1) Left Terminal Group R— Symbol C_(n)H_(2n+1)— n-C_(n)H_(2n+1)O— nO- C_(m)H_(2m+1)OC_(n)H_(2n)— mOn- CH₂═CH— V—C_(n)H_(2n+1)—CH═CH— nV- CH₂═CH—C_(n)H_(2n)— Vn-C_(m)H_(2m+1)—CH═CH—C_(n)H_(2n)— mVn- CF₂═CH— VFF— CF₂═CH—C_(n)H_(2n)—VFFn- (2) Right Terminal Group —R Symbol —C_(n)H_(2n+1) -n—OC_(n)H_(2n+1) -On —CH═CH₂ —V —CH═CH—C_(n)H_(2n+1) -Vn—C_(n)H_(2n)—CH═CH₂ -nV —CH═CF₂ —VFF —F —F —Cl -CL —OCF₃ —OCF3—C_(n)H_(2n)CF₃ -nCF3 —VCF₃ —VCF3 (3) Bonding Group —Zn— Symbol —C₂H₄— 2—COO— E —CH═CH— V —C≡C— T —CF₂O— X (4) Ring structure -An- Symbol

H

B

B(F)

B(2F)

B(F,F)

B(2F,5F)

Py

G (5) Example of Description Example 1 3-HHB(F,F)—VCF3

Example 2 3-HB-CL

Example 3 V2-BB(F)B-1

Example 4 3-BB(F,F)XB(F)—OCF3

Comparative Example 1

Example 19 was selected from the compositions disclosed in JPH10-101598A/1998.-. The basis is that the composition contains acompound (1-1-1), (1-3-1), (4-2) and (5-2-3-1), and has the smallestviscosity. The components and characteristics of the composition were asfollows.

3-B(F)B(F,F)B(F)-CL (—) 2% 3-BB(F,F)B(F,F)-F (—) 2% 3-B(F)B(F)B(F,F)-F(—) 2% 3-BB(F,F)B(F)-OCF3 (1-1-1) 2% 3-B(F)B(F)B(F,F)-OCF2H (—) 2%5-HB-F (4-2) 12% 6-HB-F (4-2) 9% 7-HB-F (4-2) 7% 2-HHB-OCF3 (1-3) 7%3-HHB-OCF3 (1-3) 11% 4-HHB-OCF3 (1-3) 7% 5-HHB-OCF3 (1-3) 5% 3-HH2B-OCF3(—) 4% 5-HH2B-OCF3 (—) 4% 3-HHB(F,F)-OCF3 (1-3-1) 5% 3-HBB(F)-F (4) 10%3-HH2B(F)-F (4) 3% 3-HB(F)BH3 (5-2-3-1) 3% 5-HBBH-3 (5-2) 3% NI = 81.4°C.; Δn = 0.098; Δε = 6.3; η = 16.9 mPa · s

Example 1

3-BB(F,F)B(F)-OCF3 (1-1-1) 10% 3-HH-V (2-1) 39% 1-BB(F)B-2V (3-1) 3%2-BB(F)B-2V (3-1) 8% 3-BB(F)B-2V (3-1) 6% 3-HHXB(F,F)-F (4-12-1) 7%3-BB(F,F)XB(F,F)-F (4-13-1) 6% 3-BB(F)B(F,F)XB(F,F)-F (4-17-1) 2%4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 8% V-HHB-1 (5-2-1-1) 11% NI = 80.4° C.;Δn = 0.125; Δε = 6.1; η = 14.2 mPa · s

Example 2

3-BB(F,F)B(F)-OCF3 (1-1-1) 4% 3-B(F)B(F,F)B(F,F)-OCF3 (1-1-4) 3%3-HB(F,F)B(F)-OCF3 (1-2-1) 3% 3-HH-V (2-1) 28% 3-HH-V1 (2-1) 10%2-BB(F)B-3 (3-1) 13% 2-BB(F)B-5 (3-1) 5% 3-HBB(F,F)-F (4-7-1) 5%3-BB(F)B(F,F)-F (4-11-1) 5% 3-BB(F,F)XB(F,F)-F (4-13-1) 7%4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 5% V-HHB-1 (5-2-1-1) 6% V2-HHB-1(5-2-1-1) 6% NI = 74.0° C.; Δn = 0.127; Δε = 5.1; η = 14.6 mPa · s

Example 3

3-BB(F,F)B(F)-OCF3 (1-1-1) 5% 3-BB(F)B(F,F)-OCF3 (1-1-2) 5% 2-HH-3 (2-1)15% 3-HH-4 (2-1) 15% V2-BB(F)B-1 (3-1) 4% 1-BB(F)B-2V (3-1) 4%2-BB(F)B-2V (3-1) 4% 1V2-BB-F (4-1-1) 3% 1V2-BB-CL (4-1-2) 3%3-BB(F,F)XB(F,F)-F (4-13-1) 10% 3-HB-CL (4-2-1) 6%4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 5% 3-HHB-1 (5-2-1-1) 8% V-HHB-1(5-2-1-1) 13% NI = 78.7° C.; Δn = 0.127; Δε = 5.0; η = 10.2 mPa · s

Example 4

3-BB(F,F)B(F)-OCF3 (1-1-1) 6% 3-HB(F)B(F,F)-OCF3 (1-2-2) 3%3-HB(F,F)B(F,F)-OCF3 (1-2-3) 4% 3-HH-V (2-1) 38% 1-BB(F)B-2V (3-1) 8%2-BB(F)B-2V (3-1) 8% 3-BB(F)B-2V (3-1) 8% 3-HHXB(F,F)-F (4-12-1) 3%3-HBB(F,F)-F (4-7-1) 11% V2-BB-1 (5-1-1-1) 2% 4-BB(F)B(F,F)XB(F,F)-F(4-17-1) 9% NI = 74.8° C.; Δn = 0.135; Δε = 5.1; η = 13.1 mPa · s

Example 5

3-BB(F,F)B(F)-OCF3 (1-1-1) 5% 3-HH-V (2-1) 40% 1-BB(F)B-2V (3-1) 5%2-BB(F)B-2V (3-1) 7% 3-PyBB-F (4-10-1) 5% 4-PyBB-F (4-10-1) 5% 5-PyBB-F(4-10-1) 5% 3-HB-CL (4-2-1) 15% 7-HB-1 (5-1) 5% V-HHB-1 (5-2-1-1) 8% NI= 73.3° C.; Δn = 0.127; Δε = 2.8; η = 5.7 mPa · s

Example 6

3-BB(F,F)B(F)-OCF3 (1-1-1) 4% 3-HHB(F,F)-OCF3 (1-3-1) 3% 3-HH-V (2-1)48% 3-HH-V1 (2-1) 7% 1-BB(F)B-2V (3-1) 8% 2-BB(F)B-2V (3-1) 9%3-BB(F)B-2V (3-1) 8% 4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 8% V-HHB-1(5-2-1-1) 5% NI = 74.3° C.; Δn = 0.123; Δε = 3.1; η = 9.0 mPa · s

Example 7

3-BB(F,F)B(F)-OCF3 (1-1-1) 5% 5-HH-V (2-1) 20% 3-HH-V1 (2-1) 10%2-BB(F)B-3 (3-1) 8% 3-HHB(F,F)-F (4-5-1) 5% 3-HHXB(F,F)-F (4-12-1) 5%3-HBB(F,F)-F (4-7-1) 10% 3-HHB-CL (4-4-1) 5% 3-HHBB(F,F)-F (4-14-1) 3%4-HHBB(F,F)-F (4-14-1) 3% 5-HHBB(F,F)-F (4-14-1) 2% 3-HB-O2 (5-1) 4%3-HHB-1 (5-2-1-1) 3% 5-HBB(F)B-2 (5-2-4-1) 4% 3-HHEBH-3 (5-2-5-1) 5%3-BB(F,F)XB(F)-OCF3 (—) 8% NI = 101.1° C.; Δn = 0.126; Δε = 4.6; η =22.1 mPa · s

Example 8

3-BB(F,F)B(F)-OCF3 (1-1-1) 5% 3-HB(F,F)B(F)-OCF3 (1-2-1) 2%3-HHB(F)-OCF3 (1-3-2) 3% 3-HH-4 (2-1) 18% 3-HH-VFF (2) 8% V2-BB(F)B-1(3-1) 6% 3-HHB(F,F)-F (4-5-1) 7% 3-HHXB(F,F)-F (4-12-1) 8%3-BB(F,F)XB(F,F)-F (4-13-1) 5% 3-HBEB(F,F)-F (4) 3% 3-HHEB(F,F)-F (4) 5%5-GHB(F,F)-F (4-9-1) 7% 3-BB(F,F)XB(F)-F (4) 5% 3-GHXB(F,F)-F (4) 5%3-HHB(F)B(F,F)-F (4-15-1) 5% 3-HB(F)B(F,F)XB(F,F)-F (4-16-1) 5%3-HHEBH-3 (5-2-5-1) 3% NI = 81.0° C.; Δn = 0.109; Δε = 9.4; η = 27.9 mPa· s

Example 9

3-BB(F,F)B(F)-OCF3 (1-1-1) 5% 3-BB(F,F)B(F,F)-OCF3 (1-1-3) 5% 3-HH-V(2-1) 30% 1-BB(F)B-2V (3-1) 5% 2-BB(F)B-2V (3-1) 6% 1V2-BB-F (4-1-1) 3%3-BB(F)B(F,F)-F (4-11-1) 5% 3-BB(F,F)XB(F,F)-F (4-13-1) 5%3-BB(F)B(F,F)XB(F,F)-F (4-17-1) 3% 4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 5%V2-BB-1 (5-1-1-1) 6% 1V2-BB-1 (5-1-1-1) 4% 3-HBB-2 (5-2-2-1) 3% 1V-HBB-2(5-2-2-1) 3% 5-HBBH-3 (5-2) 3% 5-HB(F)BH-3 (5-2-3-1) 2% 5-HBB(F)B-2(5-2-4-1) 4% 5-HBB(F)B-3 (5-2-4-1) 3% NI = 89.3° C.; Δn = 0.152; Δε =5.9; η = 14.6 mPa · s

Example 10

3-BB(F,F)B(F)-OCF3 (1-1-1) 6% 3-BB(F)B(F,F)-OCF3 (1-1-2) 4% 3-HH-4 (2-1)20% 2-BB(F)B-3 (3-1) 7% 3-HHXB(F,F)-F (4-12-1) 15% 3-HGB(F,F)-F (4-8-1)7% 5-GHB(F,F)-F (4-9-1) 10% 3-GHXB(F,F)-F (4) 3% 4-BB(F)B(F,F)XB(F,F)-F(4-17-1) 8% 3-HHB-1 (5-2-1-1) 5% V-HHB-1 (5-2-1-1) 5% 3-HHEBH-3(5-2-5-1) 3% 1O1-HBBH-5 (—) 3% 3-HHXB(F)-OCF3 (—) 4% NI = 99.8° C.; Δn =0.116; Δε = 8.5; η = 27.5 mPa · s

Example 11

3-BB(F,F)B(F)-OCF3 (1-1-1) 7% 3-HB(F,F)B(F)-OCF3 (1-2-1) 4% 2-HH-3 (2-1)10% 3-HH-V (2-1) 36% V2-BB(F)B-1 (3-1) 4% V2-BB(F)B-2 (3-1) 4%1-BB(F)B-2V (3-1) 4% 2-BB(F)B-2V (3-1) 4% 3-BB(F)B(F,F)-F (4-11-1) 5%3-BB(F,F)XB(F,F)-F (4-13-1) 4% 4-BB(F)B(F,F)XB(F,F)-F (4-17-1) 3%V2-BB-1 (5-1-1-1) 3% V-HHB-1 (5-2-1-1) 4% 3-HBB-2 (5-2-2-1) 4% 1V-HBB-2(5-2-2-1) 4% NI = 70.9° C.; Δn = 0.122; Δε = 3.4; η = 8.2 mPa · s

Example 12

3-BB(F,F)B(F)-OCF3 (1-1-1) 6% 3-BB(F)B(F,F)-OCF3 (1-1-2) 3%3-BB(F,F)B(F,F)-OCF3 (1-1-3) 3% 2-HH-3 (2-1) 5% 3-HH-V (2-1) 32%1-BB(F)B-2V (3-1) 5% 2-BB(F)B-2V (3-1) 6% 2-BB(F)B-3 (3-1) 6% 1V2-BB-F(4-1-1) 3% 3-HBB(F,F)-F (4-7-1) 7% 3-BB(F,F)XB(F,F)-F (4-13-1) 9%3-HBB-F (4-6-1) 3% 3-HHBB(F,F)-F (4-14-1) 4% 4-HHBB(F,F)-F (4-14-1) 3%V2-BB-1 (5-1-1-1) 2% V-HHB-1 (5-2-1-1) 3% NI = 72.1° C.; Δn = 0.124; Δε= 4.4; η = 12.5 mPa · s

Example 13

3-BB(F,F)B(F)-OCF3 (1-1-1) 8% 3-HH-V (2-1) 38% 1-BB(F)B-2V (3-1) 4%2-BB(F)B-2V (3-1) 4% 3-PyBB-F (4-10-1) 6% 4-PyBB-F (4-10-1) 5% 5-PyBB-F(4-10-1) 5% 3-BB(F,F)XB(F,F)-F (4-13-1) 8% 3-HB-CL (4-2-1) 8%5-GHB(F,F)-F (4-9-1) 4% V-HHB-1 (5-2-1-1) 7% 3-HBB-2 (5-2-2-1) 3% NI =75.1° C.; Δn = 0.126; Δε = 5.4; η = 13.3 mPa · s

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the disclosure has beenmade only by way of example, and that numerous changes in the conditionsand order of steps can be resorted to by those skilled in the artwithout departing from the spirit and scope of the invention.

1. A liquid crystal composition having a nematic phase comprising threecomponents, wherein the first component is at least one compoundselected from the group of compounds represented by formula (1), and thesecond component is at least one compound selected from the group ofcompounds represented by formula (2), and the third component is atleast one compound selected from the group of compounds represented byformula (3):

wherein R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons or alkenyl having 2 to 12 carbons oralkenyl having 2 to 12 carbons in which arbitrary hydrogen is replacedby fluorine; ring A is 1,4-cyclohexylene; 1,4-phenylene;2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene; ring B is1,4-phenylene; 2-fluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene andX¹, X², X³ and X⁴ are each independently hydrogen or fluorine.
 2. Theliquid crystal composition according to claim 1, wherein the firstcomponent is at least one compound selected from the group of compoundsrepresented by formulas (1-1) to (1-2):

wherein R³ is alkyl having 1 to 12 carbons, or alkenyl having 1 to 12carbons; and X¹, X², X³, X⁴, X⁵ and X⁶ are each independently hydrogenor fluorine.
 3. The liquid crystal composition according to claim 2,wherein the first component is at least one compound selected from thegroup of compounds represented by formula (1-1).
 4. The liquid crystalcomposition according to claim 1, wherein a ratio of the first componentis from approximately 5% by weight to approximately 40% by weight, and aratio of the second component is from approximately 15% by weight toapproximately 65% by weight, and a ratio of the third component is fromapproximately 5% by weight to approximately 40% by weight, based on thetotal weight of the liquid crystal composition.
 5. The liquid crystalcomposition according to claim 1, wherein the composition furthercomprises at least one compound selected from the group of compoundsrepresented by formula (4) as a fourth component:

wherein R¹ is alkyl having 1 to 12 carbons, alkoxy having 1 to 12carbons, alkenyl having 2 to 12 carbons or alkenyl having 2 to 12carbons in which arbitrary hydrogen is replaced by fluorine; X¹ and X²are each independently hydrogen or fluorine, ring C is independently1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene,2,6-difluoro-1,4-phenylene; 1,3-dioxan-2,5-diyl, or pyrimidine-2,5-diyl;Z¹ is independently a single bond, ethylene or carbonyloxy, ordifluoromethyleneoxy; Y¹ is fluorine or chlorine; and p is 1, 2 or
 3. 6.The liquid crystal composition according to claim 5, wherein the fourthcomponent is at least one compound selected from the group of compoundsrepresented by formulas (4-1) to (4-17):

wherein R³ is alkyl having 1 to 12 carbons, alkenyl having 2 to 12carbons; Y¹ is fluorine or chlorine.
 7. The liquid crystal compositionaccording to claim 6, wherein the fourth component is at least onecompound selected from the group of compounds represented by formula(4-10).
 8. The liquid crystal composition according to claim 6, whereinthe fourth component is at least one compound selected from the group ofcompounds represented by formula (4-12).
 9. The liquid crystalcomposition according to claim 6, wherein the fourth component is atleast one compound selected from the group of compounds represented byformula (4-13).
 10. The liquid crystal composition according to claim 6,wherein the fourth component is at least one compound selected from thegroup of compounds represented by formula (4-17).
 11. The liquid crystalcomposition according to claim 6, wherein the fourth component is amixture of at least one compound selected from the group of compoundsrepresented by formula (4-13) and at least one compound selected fromthe group of compounds represented by formula (4-17).
 12. The liquidcrystal composition according to claim 5, wherein a ratio of the fourthcomponent is from approximately 5% by weight to approximately 65% byweight based on the total weight of the liquid crystal composition. 13.The liquid crystal composition according to claim 1, wherein the fifthcomponent is at least one compound selected from the group of compoundsrepresented by formulas (5-1) and (5-2):

wherein, R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine; ring D is 1,4-cyclohexylene or 1,4-phenylene; ring E and ringF are each independently 1,4-cyclohexylene, 1,4-phenylene,2-fluoro-1,4-phenylene; and Z² is independently a single bond, ethyleneor carbonyloxy ; and q is 1 or
 2. 14. The liquid crystal compositionaccording to claim 13, wherein the fifth component is at least onecompound selected from the group of compounds represented by formulas(5-1-1), (5-2-1) to (5-2-5):

wherein, R¹ and R² are each independently alkyl having 1 to 12 carbons,alkoxy having 1 to 12 carbons, alkenyl having 2 to 12 carbons or alkenylhaving 2 to 12 carbons in which arbitrary hydrogen is replaced byfluorine.
 15. The liquid crystal composition according to claim 14,wherein the fifth component is at least one compound selected from thegroup of compounds represented by formula (5-1-1).
 16. The liquidcrystal composition according to claim 14, wherein the fifth componentis at least one compound selected from the group of compoundsrepresented by formula (5-2-1).
 17. The liquid crystal compositionaccording to claim 14, wherein the fifth component is a mixture of atleast one compound selected from the group of compounds represented byformula (5-1-1) and at least one compound selected from the group ofcompounds represented by formula (5-2-1).
 18. The liquid crystalcomposition according to claim 13, wherein a ratio of the fifthcomponent is from approximately 3% by weight to approximately 40% byweight, based on the total weight of the liquid crystal composition. 19.The liquid crystal composition according to claim 1, wherein thecomposition has a maximum temperature of a nematic phase ofapproximately 65° C. or more, an optical anisotropy (25° C.) at awavelength of 589 nm of approximately 0.08 or more, and a dielectricanisotropy (25° C.) at a frequency of 1 kHz of approximately 2 or more.20. A liquid display device that includes the liquid crystal compositionaccording to claim
 1. 21. The liquid crystal display device according toclaim 20, wherein the liquid crystal display device has an operationmode of a TN mode, an OCB mode an IPS mode or PSA mode and has a drivingmode of an active matrix mode.